Concrete Calculators

Concrete calculators cover slabs, footings, columns, and block walls, everything you need to figure out cubic yards, bag counts, and cost before you order or mix.

Frequently asked questions

Should I order ready-mix concrete or buy bags?

Bags make sense for small pours, a post hole, a small pad, repairs. Once a job passes roughly one cubic yard (about 45 eighty-pound bags), ready-mix delivery is usually cheaper, faster, and gives a more consistent mix.

How thick should a concrete slab be?

Four inches is standard for patios, walkways, and shed pads. Driveways carrying passenger vehicles use 4-5 inches; anything supporting trucks or RVs should be 5-6 inches over a proper compacted base.

Why do concrete estimates include extra volume?

Coming up short mid-pour is far worse than having a little left over, a cold joint between two pours weakens the slab. Most contractors order 5-10% beyond the calculated volume to cover uneven subgrade and spillage.